Convert last_reset timestamps to UTC (#56561)

* Convert last_reset timestamps to UTC

* Add test

* Apply suggestion from code review

homeassistant/components/sensor/recorder.py

@@ -312,6 +312,21 @@ def _wanted_statistics(
     return wanted_statistics
 
 
+def _last_reset_as_utc_isoformat(
+    last_reset_s: str | None, entity_id: str
+) -> str | None:
+    """Parse last_reset and convert it to UTC."""
+    if last_reset_s is None:
+        return None
+    last_reset = dt_util.parse_datetime(last_reset_s)
+    if last_reset is None:
+        _LOGGER.warning(
+            "Ignoring invalid last reset '%s' for %s", last_reset_s, entity_id
+        )
+        return None
+    return dt_util.as_utc(last_reset).isoformat()
+
+
 def compile_statistics(  # noqa: C901
     hass: HomeAssistant, start: datetime.datetime, end: datetime.datetime
 ) -> list[StatisticResult]:
@@ -424,7 +439,11 @@ def compile_statistics(  # noqa: C901
                 reset = False
                 if (
                     state_class != STATE_CLASS_TOTAL_INCREASING
-                    and (last_reset := state.attributes.get("last_reset"))
+                    and (
+                        last_reset := _last_reset_as_utc_isoformat(
+                            state.attributes.get("last_reset"), entity_id
+                        )
+                    )
                     != old_last_reset
                 ):
                     if old_state is None:

tests/components/sensor/test_recorder.py

@@ -50,6 +50,16 @@ GAS_SENSOR_ATTRIBUTES = {
 }
 
 
+@pytest.fixture(autouse=True)
+def set_time_zone():
+    """Set the time zone for the tests."""
+    # Set our timezone to CST/Regina so we can check calculations
+    # This keeps UTC-6 all year round
+    dt_util.set_default_time_zone(dt_util.get_time_zone("America/Regina"))
+    yield
+    dt_util.set_default_time_zone(dt_util.get_time_zone("UTC"))
+
+
 @pytest.mark.parametrize(
     "device_class,unit,native_unit,mean,min,max",
     [
@@ -338,14 +348,121 @@ def test_compile_hourly_sum_statistics_amount_reset_every_state_change(
         "unit_of_measurement": unit,
         "last_reset": None,
     }
-    seq = [10, 15, 15, 15, 20, 20, 20, 10]
+    seq = [10, 15, 15, 15, 20, 20, 20, 25]
     # Make sure the sequence has consecutive equal states
     assert seq[1] == seq[2] == seq[3]
 
+    # Make sure the first and last state differ
+    assert seq[0] != seq[-1]
+
     states = {"sensor.test1": []}
+
+    # Insert states for a 1st statistics period
     one = zero
     for i in range(len(seq)):
         one = one + timedelta(seconds=5)
+        attributes = dict(attributes)
+        attributes["last_reset"] = dt_util.as_local(one).isoformat()
+        _states = record_meter_state(
+            hass, one, "sensor.test1", attributes, seq[i : i + 1]
+        )
+        states["sensor.test1"].extend(_states["sensor.test1"])
+
+    # Insert states for a 2nd statistics period
+    two = zero + timedelta(minutes=5)
+    for i in range(len(seq)):
+        two = two + timedelta(seconds=5)
+        attributes = dict(attributes)
+        attributes["last_reset"] = dt_util.as_local(two).isoformat()
+        _states = record_meter_state(
+            hass, two, "sensor.test1", attributes, seq[i : i + 1]
+        )
+        states["sensor.test1"].extend(_states["sensor.test1"])
+
+    hist = history.get_significant_states(
+        hass,
+        zero - timedelta.resolution,
+        two + timedelta.resolution,
+        significant_changes_only=False,
+    )
+    assert dict(states)["sensor.test1"] == dict(hist)["sensor.test1"]
+
+    recorder.do_adhoc_statistics(start=zero)
+    recorder.do_adhoc_statistics(start=zero + timedelta(minutes=5))
+    wait_recording_done(hass)
+    statistic_ids = list_statistic_ids(hass)
+    assert statistic_ids == [
+        {"statistic_id": "sensor.test1", "unit_of_measurement": native_unit}
+    ]
+    stats = statistics_during_period(hass, zero, period="5minute")
+    assert stats == {
+        "sensor.test1": [
+            {
+                "statistic_id": "sensor.test1",
+                "start": process_timestamp_to_utc_isoformat(zero),
+                "end": process_timestamp_to_utc_isoformat(zero + timedelta(minutes=5)),
+                "max": None,
+                "mean": None,
+                "min": None,
+                "last_reset": process_timestamp_to_utc_isoformat(dt_util.as_local(one)),
+                "state": approx(factor * seq[7]),
+                "sum": approx(factor * (sum(seq) - seq[0])),
+                "sum_decrease": approx(factor * 0.0),
+                "sum_increase": approx(factor * (sum(seq) - seq[0])),
+            },
+            {
+                "statistic_id": "sensor.test1",
+                "start": process_timestamp_to_utc_isoformat(
+                    zero + timedelta(minutes=5)
+                ),
+                "end": process_timestamp_to_utc_isoformat(zero + timedelta(minutes=10)),
+                "max": None,
+                "mean": None,
+                "min": None,
+                "last_reset": process_timestamp_to_utc_isoformat(dt_util.as_local(two)),
+                "state": approx(factor * seq[7]),
+                "sum": approx(factor * (2 * sum(seq) - seq[0])),
+                "sum_decrease": approx(factor * 0.0),
+                "sum_increase": approx(factor * (2 * sum(seq) - seq[0])),
+            },
+        ]
+    }
+    assert "Error while processing event StatisticsTask" not in caplog.text
+
+
+@pytest.mark.parametrize("state_class", ["measurement"])
+@pytest.mark.parametrize(
+    "device_class,unit,native_unit,factor",
+    [
+        ("energy", "kWh", "kWh", 1),
+    ],
+)
+def test_compile_hourly_sum_statistics_amount_invalid_last_reset(
+    hass_recorder, caplog, state_class, device_class, unit, native_unit, factor
+):
+    """Test compiling hourly statistics."""
+    zero = dt_util.utcnow()
+    hass = hass_recorder()
+    recorder = hass.data[DATA_INSTANCE]
+    setup_component(hass, "sensor", {})
+    attributes = {
+        "device_class": device_class,
+        "state_class": state_class,
+        "unit_of_measurement": unit,
+        "last_reset": None,
+    }
+    seq = [10, 15, 15, 15, 20, 20, 20, 25]
+
+    states = {"sensor.test1": []}
+
+    # Insert states
+    one = zero
+    for i in range(len(seq)):
+        one = one + timedelta(seconds=5)
+        attributes = dict(attributes)
+        attributes["last_reset"] = dt_util.as_local(one).isoformat()
+        if i == 3:
+            attributes["last_reset"] = "festivus"  # not a valid time
         _states = record_meter_state(
             hass, one, "sensor.test1", attributes, seq[i : i + 1]
         )
@@ -375,7 +492,7 @@ def test_compile_hourly_sum_statistics_amount_reset_every_state_change(
                 "max": None,
                 "mean": None,
                 "min": None,
-                "last_reset": process_timestamp_to_utc_isoformat(one),
+                "last_reset": process_timestamp_to_utc_isoformat(dt_util.as_local(one)),
                 "state": approx(factor * seq[7]),
                 "sum": approx(factor * (sum(seq) - seq[0])),
                 "sum_decrease": approx(factor * 0.0),
@@ -384,6 +501,7 @@ def test_compile_hourly_sum_statistics_amount_reset_every_state_change(
         ]
     }
     assert "Error while processing event StatisticsTask" not in caplog.text
+    assert "Ignoring invalid last reset 'festivus' for sensor.test1" in caplog.text
 
 
 @pytest.mark.parametrize("state_class", ["measurement"])
@@ -413,6 +531,8 @@ def test_compile_hourly_sum_statistics_nan_inf_state(
     one = zero
     for i in range(len(seq)):
         one = one + timedelta(seconds=5)
+        attributes = dict(attributes)
+        attributes["last_reset"] = dt_util.as_local(one).isoformat()
         _states = record_meter_state(
             hass, one, "sensor.test1", attributes, seq[i : i + 1]
         )
@@ -1685,7 +1805,11 @@ def test_compile_statistics_hourly_summary(hass_recorder, caplog):
         start_meter = start
         for j in range(len(seq)):
             _states = record_meter_state(
-                hass, start_meter, "sensor.test4", sum_attributes, seq[j : j + 1]
+                hass,
+                start_meter,
+                "sensor.test4",
+                sum_attributes,
+                seq[j : j + 1],
             )
             start_meter = start + timedelta(minutes=1)
             states["sensor.test4"] += _states["sensor.test4"]
@@ -1955,7 +2079,7 @@ def record_meter_states(hass, zero, entity_id, _attributes, seq):
     return four, eight, states
 
 
-def record_meter_state(hass, zero, entity_id, _attributes, seq):
+def record_meter_state(hass, zero, entity_id, attributes, seq):
     """Record test state.
 
     We inject a state update for meter sensor.
@@ -1967,10 +2091,6 @@ def record_meter_state(hass, zero, entity_id, _attributes, seq):
         wait_recording_done(hass)
         return hass.states.get(entity_id)
 
-    attributes = dict(_attributes)
-    if "last_reset" in _attributes:
-        attributes["last_reset"] = zero.isoformat()
-
     states = {entity_id: []}
     with patch("homeassistant.components.recorder.dt_util.utcnow", return_value=zero):
         states[entity_id].append(set_state(entity_id, seq[0], attributes=attributes))